Regenerative soaking pit furnace



April 940. w. MORTON Er'Al. ,321

' REGENERATIVE SOAKING FIT FURNACE Fil ed Dec. 17; 193'? 2 Sheets-Sheet 2 ATTORNEY.

Patented Apr. 9, 1940 PATENT OFFICE REGENERATIVE SOAKIN G PIT FURNACE William A. Morton, Mount Lebanon, and Howard F. Spencer, Pittsburgh, Pa., assignors to Amco,

Incorporated, Pittsbur Pennsylvania gh, Pa., a corporation of Application December 17, 1937, Serial No. 180,342

' 1 Claim.

This invention relates to new and useful improvements in apparatus for and method of heating ingots in regenerative soaking pit furnaces, and the present invention is an adaptation of the new and improved means of heating ingots disclosed in our Patent No. 2,079,560 granted May 4, 1937. 1

In the above-identified patent we have disclosed a novel method of heating ingots by assembling the ingots in spaced relation on their ends in a soaking pit chamber, and conducting the gaseous heating medium continuously from one end of the ingots between the ingots, in a path substantially parallel to a wall of the ingots, the application of the combustion fiame to the pitchamber being such as to avoid direct impingement thereof on the ingot walls. The present application discloses the same principle of heating under conditions where regenerators 20 are employed for preheating the combustion air,

as distinguished from the recuperative type apparatus disclosed in the aforementioned patent.

As will be evident from the following description of the drawings, the method of firing, as disclosed in the former patent, is applicable to regenerative soaking pit furnaces by arranging the regenerators and firing ports in such manner in relation to the ingots as to envelope the ingots in a suitable heating environment without im- 30 pinging the combustion flame on the walls thereof, thereby avoiding washing, so-called, and the excessive formation of scale.

In the accompanying drawings constituting a part hereof and in which like reference characters designate like parts:

Fig. 1 is a plan view diagrammatically illustrating a regenerative type soaking pit furnace embodying-the principles of this invention;

Fig. 2 a vertical section taken longitudinally through the furnace and regenerators;

3 a plan view diagrammatically illustrating" a regenerative type furnace modified in the location and disposition of the firing ports; and

Fig. 4 a vertical cross-sectional view thereof,

45 taken along the longitudinal centerline of Fig. 3.

With reference to Figs. 1 and 2 of the drawings, the structure therein illustrated comprises a pit i constituted by the sidewalls 2, hearth 3 and cover 4. A pair of regenerators 5, 5a, communicate through passages 6, 6a, with firing ports 1, 1a, and passages 8, 8a, extending vertically from the horizontal passages 9, 9a, leading to fuel mains l0, Illa, the latter being provided with -valves ll, Ila, for regulating the gaseous fuel supply to the-firing ports. The regenerators 5,.

5a, contain the usual checker-tile structures I 2, Ha, through which the waste gases, leaving the firing ports of the furnace, pass into the stack openings I 3, Ha, leading to a common stack l4 controlled by the usual reversing valve, not 5 shown.

As is evident from Fig. 1 of the drawings, the firing ports are disposed in the longitudinal centerline of the furnace, and the ingots l5 are arranged in rows, leaving a space therebetween 10 which may be designated the combustion space. The firing ports I, 1a, are so disposed as to project the fiame of combustion upwardly into the chamber, and the path of travel of the products of combustion'will be as shown by the broken lines.

In the operation of the furnace shown in Figs. 1 and 2, gaseous fuel is supplied in regulable quantities through passages 8 and 9 to the firing port 1 in which it commingles with superheated air drawn through the checker-tile I! of the regenerator on one side of the furnace. The flame of combustion is projected into the furnace between the parallel rows of the ingots and the products of combustion are exited through the port opposite the firing port and pass through the checker-tile of the other regenerator, thence outwardly through the waste gas passage to the stack l4. The regenerator through which the waste gases exit has its fuel supply shut off by the valve II or Ha, as the case may be. When the reversing valve is set in one position, air is supplied to one regenerator while the waste gases exit the other, and in its other position the supply of air and exiting of waste gases is reversed. The

. reversal takes place as frequently as needed to maintain the desired super-heat of the combustion air.

In the structure shown in Figs. 3 and 4 of the drawings, the soaking pit I6 is shaped to arrange the ingots around the outer wall forming a combustion space I! in to which ports l8 and, Mia enter at the base. These ports are the firing ports which communicate with regenerators I9, I 9a, through conduits 20, 20a. Fuel passages 2!, 21a. communicate with the passages 20 at the top of the regenerators and fiues 22, 22a, lead to a common stack and a source of air supply. The tile checkerwork 23, 23a, is interposed between the fines 20 and 22. In operation, air is drawn through one of the regenerators and the waste gases are exited through the other alternately, as governed by the reversing valve. The ingots 24. are heated by the flame of combustion projecting upwardly into the furnace chamber, and 5B the products of combustion passing downwardly and out, as shown by the arrows in Fig. 4, a. loop oi. hot gases extending across the ports l8, l8a and vertically into the soaking pit chamber.

From the foregoing description of the invention, it will be apparent that ingots may be heated with the combustion flame out of contact with the ingot walls, where regenerative firing is employed, by arranging the firing ports and ingots in a manner to direct the flame of combustion adjacent the ingots without impinging thereon.

Although.several embodiments of the invention have been herein illustrated and described, it will be evident to those skilled in the art that other arrangements of the ingots and firing ports are possible in regenerative firing which avoid impingement of the flame of combustion on the ingot walls.

We claim: a

A soaking pit for heating steel ingots comprising a, furnace chamber having a hearth for supporting ingots thereon, a plurality of regenerators connected to said chamber having oppositely disposed firing ports centrally of said chamber for generating loops of hot gases coextensive with the axis of the chamber, the ingot supporting hearth being of such area as to support rows of ingots on opposite sides of the regenerator ports whereby the hot gases are out of contact with the ingot walls. 

